Field of the Invention
Embodiments of the present invention relate to a technique for increasing the efficiency of a heat conversion device using a thermoelectric element.
Description of the Related Arts
In general, a thermoelectric element including a thermoelectric device has a structure in which a PN junction pair is formed by bonding a p-type thermoelectric material and an n-type thermoelectric material between metal electrodes. When a temperature difference is provided between the materials of this PN junction pair, electric power is generated by the Seebeck effect so that a thermoelectric element can serve as a power generating device. Also, the thermoelectric element may be used as a temperature controlling device by the Peltier effect in which one material of the PN junction pair is cooled and the other material is heated.
In particular, the temperature controlling device using the thermoelectric conversion element implements a cooling or heating operation by passing an external inflow medium through a heat absorption surface and a heat emitting surface.
However, since a temperature differential ΔT between a heat absorption portion of the thermoelectric conversion device from which heat absorption is generated, and a heat emitting portion from which heat emission is generated is fixed at a given applied voltage, it causes a limit in a cooling and heating temperature due to an influence on an outdoor air temperature. That is, due to the limit caused by the temperature differential generated between the heat absorption portion and the heat emitting portion, it is problematic in that it is difficult to implement thermoelectric efficiency beyond a fixed temperature differential.